Heterocyclic compound and use



United States Patent 3,393,206 HETEROCYCLIC COMPOUND AND USE Michael Cais, 21 Smolenskin St., Ahuza, Haifa, Israel, and William Taub, 43 Ben Zion St., Rehovoth, Israel No Drawing. Continuation-impart of application Ser. No. 274,928, Apr. 23, 1963. This application Feb; 15, 1966, Ser. No. 527,498

' 1 Claim. (Cl. 260-3435) ABSTRACT OF THE DISCLOSURE The compound 6-phenyl 2,3,5 trioxotetrahydropyran which is useful for preventing sludging of mammalian blood.

This application is a continuation-in-part of our copending United States application Ser. No. 274,928, filed Apr. 23, 1963, US. Patent No. 3,344,150.

This invention relates to a new method for the inhibition of sludging of blood, thrombus formation and platelet adhesiveness and, more particularly, to the novel chemical 6-phenyl-2,3,S-trioxotetrahydropyran and to its use for those purposes.

The new substance 6-phenyl-2,3,5-trioxotetrahydropyran, of this invention has valuable pharmacological properties in that, among other uses, it is an anti-inflammatory agent and an anti-coagulant and it prevents the sludging of mammalian blood by inhibiting thrombus formation and platelet adhesiveness. This is all the more surprising as the closest known representative of this type, i.e. 6,6-dimethyl-2,3,S-trioxotetrahydropyran, is virtually inactive pharmacologically. The 6-phenyl-2,3,S-trioxotetrahydropyran of the present invention is thus useful as an antithrombotic agent.

The compound of the present invetnion has the tautomeric formulae is named 6-pl1enyl-2,3,S-trioxotetrahydropyran and is prepared by the following reaction scheme:

l HCECH H O C=O OIL-CECE HgH II o M.P. 257-25s o.

The following example will illustrate in detail a method of preparing the compound of the present invention.

Example.6-phenyl-2,3,S-trioxotetrahydropyran OHO I ll on o-om was slowly added to the continuously coled and stirred reaction mixture; a shorttime after the beginning of this addition, the solution turned cloudy and a precipitate began to form. After the addition was completed, stirring was continued for another four hours. The reaction mixture was then poured into iced-Water and the aqueous mixture was extracted twice with ether to remove unreacted materials. The aqueous layer was acidified with aqueous hydrochloric acid and the yellow precipitate formed was filtered to yield about 33 g. 6-phenyl-2,3,5- trioxotetrahydropyran. Crystallization from benzene-ethyl acetate yielded white crystals of M.P. 257-258 C.

Analysis.Calcd for C H O C, 64.71; H, 3.95. Found: C, 64.98; H, 4.06.

It is known that the white thrombi which form at sites of mechanical or other injury to the skin are principally composed of agglutinated (i.e. clotted) blood platelets which gradually fuse into a granular viscous substance. It is further known that a vascular defect occurs in advance of clotting, that such defect is related to platelet adhesiveness and that such adhesiveness is promoted by certain materials such adenosine diphosphate (ADP).

As indicated above, it has now been found that the compound of this invention exhibits anticoagulation and antisludging properties (i.e. intravascular red cell aggregation), Apparently these properties result from the action of the compound of this invention in counteracting ADP action and diminishing platelet adhesiveness but this is a matter of theory and not essential to the present invention.

Various tests were performed which demonstrated the ability of the compound of this invention to decrease sludging and to increase the suspension stability of mammalian blood. One of the principal methods used was a quantitative determination of erythrocyte sedimentation rate in Westergreen tubes, using a series of dilutions of plasma or artificial colloids. One part of washed human erythrocytes was suspended in two parts of each dilution of suspension fluid. The logarithms of sedimentation rate after one hour were plotted against the logarithms of the colloids concentration in the respective tubes. The points were approximately on straight lines with nearly the same slopes. The points where the lines cut the abscissa gave the concentration of colloid which caused a sedimentation rate of 1 mm./hr. This parameter, called the critical concentration, is dependent on the colloids concentration in individual tubes and is considered a quantitative measurement of the erythrocyte aggregation power of the plasma. When the colloid concentration is lower than critical, the erythrocyte aggregation disappears and when the concentration is raised, aggregation and sedimentation rate rise very rapidly.

For the determination of the anti-aggregation properties of the compound of this invention, a fixed aggregation force was chosen, giving a sedimentation rate of 40 mm./hr. (using 1% Dextran). Increasing concentrations of the compound were added and the inhibition of aggregation was represented by a decrease in the sedimentation rate, measured in terms of the control sample. The results are illustrated in the following table.

TABLE Concentration in Sedimentation Percent Toxicity I.P., Compound mgm./cc. Rate Inhibition LD5 Mice Blood (mm./hr.)

. 1 10 74 6,6d'unethy1-2,3,5-trioxototrahydropyran. 0.5 17 55 800 I 0.25 25 at 1 0 100 G-phenyl-2,3,5 trioxotetrahydropyran 0. 5 3 95 1, 500

- 0.25 37 35 Control 38 While in the foregoing sepcification various embodi- We claim: ments of this invention have been set forth in specific 1- 6-phenyl-2,3,5-tnoxotetrahydropyran. detail and elaborated for the purpose of illustration,

.. References Clted I it will be apparent to those skilled in the art that this invention is susceptible to other embodiments and that 15 Bids et a1. Berichte 1911 pp. 408-09...

many of the details can be varied widely without de- NICHOLAS S. Ri-ZZO, Primary Examiner.

parting from the basic concept 'and the spirit and scope of the invention. J. NARCAVAGE, Assistant Examiner. 

